Unity 2d endless runner level parts not spawning - unity3d

Question

I am very new to programming.. I tried to make a endless runner with unity and I am at the point now that I want to make platforms to spawn automatically. I followed a tutorial but whenever I reach the end no new platforms are being spawned ):
Here is the code:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class TESTGAMEMANAGER : MonoBehaviour
{
private const float PLAYER_DISTANCE_SPAWN_LEVEL_PART = 50f;
[SerializeField] private Transform levelPart_Start;
[SerializeField] private List<Transform> levelPartList;
[SerializeField] private PlayerScript player;
private Vector3 lastEndPosition;
private void Awake()
{
lastEndPosition = levelPart_Start.Find("EndPoint").position;
int startingSpawnLevelParts = 5;
for (int i = 0; i < startingSpawnLevelParts; i++)
{
SpawnLevelPart();
}
}
private void Update()
{
if (Vector3.Distance(player.transform.position(), lastEndPosition) < PLAYER_DISTANCE_SPAWN_LEVEL_PART)
{
// Spawn another level part
SpawnLevelPart();
}
}
private void SpawnLevelPart()
{
Transform chosenLevelPart = levelPartList[Random.Range(0, levelPartList.Count)];
Transform lastLevelPartTransform = SpawnLevelPart(chosenLevelPart, lastEndPosition);
lastEndPosition = lastLevelPartTransform.Find("EndPoint").position;
}
private Transform SpawnLevelPart(Transform levelPart, Vector3 spawnPosition)
{
Transform levelPartTransform = Instantiate(levelPart, spawnPosition, Quaternion.identity);
return levelPartTransform;
}
}
It seems like that only at the start there are platforms but after some time I reach the end and fall down );
Anyone know how to fix that?
Unity Picture with problem